This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The central aim of this project is to develop a novel in-vivo optical skin imaging system to quantitatively characterize changes in skin that accompany dysplastic transformation. The modulated Imaging (MI) instrument uses patterned illumination to non-invasively obtain subsurface images of biological tissues. This non-contact approach enables rapid quantitative determination of the optical properties of tissues over a wide field-of-view. When combined with multi-spectral imaging, the optical properties at several wavelengths provide quantitative measures within tissues to determine the in-vivo concentrations of chromophores, including oxy- and deoxy-hemoglobin, water, lipid and melanin. Furthermore, images at various spatial frequencies can be processed to visualize depth-sectioned subsurface features in terms of scattering and absorption.Our hypothesis is that this multi-modality MI instrument can serve as an imaging platform for quantitative characterization of benign and malignant melanocytic skin lesions.